The argument is progressive enhancement: if someone doesn't have JavaScript or CSS enabled the JavaScript-enabled features would be completely hidden from view, plus you get to keep your HTML in your HTML file.
Okay I get the point for missing CSS, that makes sense...
But in the case of only JS being disabled, a hidden div will remain hidden also, thus accomplishing the exact same thing in that case.
I can see how someone might turn your external style sheets off, but an inline style="display:none" attribute is not going to be ignored by any browsers. What's so inaccessible about that?